The massive project runs from just south of downtown up to Charlestown, a few miles north. It will sink Interstate 93 - long an elevated eyesore cutting a swath through the heart of the city - underground. It will also connect Interstate 90, the Massachusetts Turnpike, to Logan Airport via the already-completed Ted Williams Tunnel.

When the project is completed in 2004 (originally, it was supposed to be finished this year), the 10-lane expressway will run beneath green space downtown. Today, that part of the city is a noisy mix of dump trucks, cranes, jackhammers, earthmovers, construction workers, and Bostonians trying to make their way to work through the maze of constantly changing detours.

The Big Dig was originally proposed by Gov. Michael Dukakis in 1983, with a price tag of $2.2 billion. Today it is well over that initial budget, and a few years behind schedule. But the tourists love it, and the local businesses don't seem to mind.